JSON processing using JQ operator in Rapidminer

Somnath_DasSomnath_Das Member Posts: 31 Maven
I have simple JSON data in the format as follows:

{"A":"a1","B":"b1"}
{"A":"a2","B":"b2"}
{"A":"a3","B":"b3"}

I want the output in the format:
A   B
a1  b1
a2  b2
a3  b3

Please help, it is urgent
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Answers

  • BalazsBaranyBalazsBarany Administrator, Moderator, Employee, RapidMiner Certified Analyst, RapidMiner Certified Expert Posts: 955 Unicorn
    Hi,

    when I try your input on jqplay.org with the filter [.A, .B] | @csv, it returns the correct output.

    The library used in the RapidMiner extension only returns the first element though. I'm not sure what to do there.

    Your input is a bit atypical because it's a list of objects, but not in a syntactically explicit way. 

    When changing the input to this:
    [
      {"A":"a1","B":"b1"},
      {"A":"a2","B":"b2"},
      {"A":"a3","B":"b3"}
    ]
    it works with the filter .[] | [.A, .B].

    Example process:

    <?xml version="1.0" encoding="UTF-8"?><process version="9.8.001">
      <context>
        <input/>
        <output/>
        <macros/>
      </context>
      <operator activated="true" class="process" compatibility="9.8.001" expanded="true" name="Process">
        <parameter key="logverbosity" value="init"/>
        <parameter key="random_seed" value="-1"/>
        <parameter key="send_mail" value="never"/>
        <parameter key="notification_email" value=""/>
        <parameter key="process_duration_for_mail" value="30"/>
        <parameter key="encoding" value="SYSTEM"/>
        <process expanded="true">
          <operator activated="true" class="text:create_document" compatibility="9.3.001" expanded="true" height="68" name="Create Document" width="90" x="112" y="34">
            <parameter key="text" value="[&#10;  {&quot;A&quot;:&quot;a1&quot;,&quot;B&quot;:&quot;b1&quot;},&#10;  {&quot;A&quot;:&quot;a2&quot;,&quot;B&quot;:&quot;b2&quot;},&#10;  {&quot;A&quot;:&quot;a3&quot;,&quot;B&quot;:&quot;b3&quot;}&#10;]"/>
            <parameter key="add label" value="false"/>
            <parameter key="label_type" value="nominal"/>
          </operator>
          <operator activated="true" class="multiply" compatibility="9.8.001" expanded="true" height="103" name="Multiply" width="90" x="246" y="34"/>
          <operator activated="true" class="text:json_to_data" compatibility="9.3.001" expanded="true" height="82" name="JSON To Data" width="90" x="380" y="34">
            <parameter key="ignore_arrays" value="false"/>
            <parameter key="limit_attributes" value="false"/>
            <parameter key="skip_invalid_documents" value="false"/>
            <parameter key="guess_data_types" value="true"/>
            <parameter key="keep_missing_attributes" value="false"/>
            <parameter key="missing_values_aliases" value=", null, NaN, missing"/>
          </operator>
          <operator activated="true" class="json_processing_with_jq:process_document_with_jq" compatibility="0.8.001" expanded="true" height="68" name="Process Document with jq" width="90" x="380" y="136">
            <parameter key="indent_json" value="true"/>
            <parameter key="jq_expression" value=".[] | [.A, .B]"/>
            <parameter key="output_format" value="csv"/>
          </operator>
          <operator activated="true" class="text:write_document" compatibility="9.3.001" expanded="true" height="82" name="Write Document" width="90" x="514" y="136">
            <parameter key="overwrite" value="true"/>
            <parameter key="encoding" value="SYSTEM"/>
          </operator>
          <operator activated="true" class="read_csv" compatibility="9.8.001" expanded="true" height="68" name="Read CSV" width="90" x="648" y="136">
            <parameter key="column_separators" value=","/>
            <parameter key="trim_lines" value="false"/>
            <parameter key="use_quotes" value="true"/>
            <parameter key="quotes_character" value="&quot;"/>
            <parameter key="escape_character" value="\"/>
            <parameter key="skip_comments" value="false"/>
            <parameter key="comment_characters" value="#"/>
            <parameter key="starting_row" value="1"/>
            <parameter key="parse_numbers" value="true"/>
            <parameter key="decimal_character" value="."/>
            <parameter key="grouped_digits" value="false"/>
            <parameter key="grouping_character" value=","/>
            <parameter key="infinity_representation" value=""/>
            <parameter key="date_format" value=""/>
            <parameter key="first_row_as_names" value="false"/>
            <list key="annotations"/>
            <parameter key="time_zone" value="SYSTEM"/>
            <parameter key="locale" value="English (United States)"/>
            <parameter key="encoding" value="SYSTEM"/>
            <parameter key="read_all_values_as_polynominal" value="false"/>
            <list key="data_set_meta_data_information">
              <parameter key="0" value="A.true.nominal.attribute"/>
              <parameter key="1" value="B.true.nominal.attribute"/>
            </list>
            <parameter key="read_not_matching_values_as_missings" value="true"/>
            <parameter key="datamanagement" value="double_array"/>
            <parameter key="data_management" value="auto"/>
          </operator>
          <connect from_op="Create Document" from_port="output" to_op="Multiply" to_port="input"/>
          <connect from_op="Multiply" from_port="output 1" to_op="JSON To Data" to_port="documents 1"/>
          <connect from_op="Multiply" from_port="output 2" to_op="Process Document with jq" to_port="input 1"/>
          <connect from_op="JSON To Data" from_port="example set" to_port="result 1"/>
          <connect from_op="Process Document with jq" from_port="result 1" to_op="Write Document" to_port="document"/>
          <connect from_op="Write Document" from_port="file" to_op="Read CSV" to_port="file"/>
          <connect from_op="Read CSV" from_port="output" to_port="result 2"/>
          <portSpacing port="source_input 1" spacing="0"/>
          <portSpacing port="sink_result 1" spacing="0"/>
          <portSpacing port="sink_result 2" spacing="0"/>
          <portSpacing port="sink_result 3" spacing="0"/>
        </process>
      </operator>
    </process>


    With this input the output of "JSON to Data" is also meaningful.


    Regards,

    Balázs

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